Clean drinking water is a matter of life and death. Our human body consist of 50-70% water and the quality of water which we consume matters because unclean water is a sure predictor of shortened life expectancy. Although we may have the luxury of access to fairly clean water, there are still chemicals and contaminants in our water supply. The safest is to take matters into our own hands. Understand how each of the 13 types of water filtration and purification method works below and apply it to your home to get the best possible quality of drinking water that you can afford.
According to a recent United Nations report, unclean water is a sure predictor of shortened life expectancy. The importance of clean water cannot be overstated.
Is the most commonly used method to purify water. Water that is to be boiled should always be clear. It is easier with a kettle as it whistles once it is ready to be turned off. Otherwise if using other types of simple container, once boiling, you should continue for about 2 to 3 more minutes before removing the heat.
- Kills almost every living thing and vaporizes most chemicals.
- Metals become more concentrated.
Slow Sand Filter
Also referred to as biosand or biological sand filter. A slow sand filter is comprised of a bed of graded sand which is supported by a layer of gravel. This filter media is confined in a box with openings at both ends allowing water to flow in and out, while operating on a top-down, gravity basis.
- Solids and water muddiness is naturally filtered.
- Some bacteria still remains.
These filters contain cellulose, rayon or some other material spun into a mesh with small pores. It is just like pouring water containing sand through a piece of cloth. Unlike slow sand filter, pressure is applied to force water through tightly wrapped fibers. There are many kinds of fiber filters in the market that comes in a variety of shapes and sizes from fine to coarse meshes. Go for fiber filters with micron ratings lower than 1 to efficiently trap particles.
- Sediment and muddiness is removed.
- Small organic particles that causes bad odors and taste may also be removed.
- The lower the micron ratings, the more often the filter must be changed.
- Anything that is dissolved in water like chlorine, lead and mercury is not removed.
Almost exactly like fiber filters which will provide only mechanical filtration. Again, go for pore sizes that are less than 1 micron. 0.5 micron if possible.
- Reduces asbestos fibers that may come from the degradation or breakdown of human-made products such as insulation, pipes, etc.
- Works against certain bacteria.
- Chlorine, lead, mercury and other organic compounds stays in the water.
Activated Carbon / Charcoal Filter
Charcoal is carbon. Activated charcoal is charcoal that has been treated with oxygen to open up millions of tiny pores between the carbon atoms. The use of special manufacturing techniques results in highly porous charcoals that have surface areas of 300-2,000 square meters/gram. These activated charcoals are then used to adsorb substances from liquids. Adsorb basically means attaching by chemical reaction. Activated charcoal with a fairly wide surface area has countless potential for bonding chemicals to the surface. Activated charcoal is good at trapping other carbon-based impurities, as well as things like chlorine. Many other chemicals like sodium and nitrate are not attracted to carbon at all so they pass right through. This means that an activated charcoal filter will remove certain impurities while ignoring others. It also means that, once all of the bonding sites are filled, an activated charcoal filter stops working. At that point you must replace the filter.
Granular Activated Charcoal / Carbon Filter
Although activated charcoal granules are loose, they are an effective and valuable water treatment device. As long as a uniform flow rate is maintained and the filter is changed according to the manufacturer’s specifications, optimal performance is achieved.
- Reduces chlorine, particles and improves the taste and odor of water.
- Water flow is reasonably maintained and is suitable for use as a whole house filter.
- Typical filter cartridge changes are done annually.
- Zero electricity is used.
- Zero water is wasted.
- Beneficial minerals such as calcium, magnesium and potassium that are dissolved in the water, stays in the water.
- Water can flow around the granules without being treated as water flows where there is less resistance.
- Water can carve a channel where it may flow freely with little resistance, avoiding contact with the filtration medium.
- Pockets of contaminants can form around the granules that will result in a collapse, which contaminates the filtered flow of water, as the pressure changes.
- General pitcher filters containing active carbon granules have fairly large effective pore sizes of more than 20 microns.
- May potentially become breeding grounds for trapped bacteria when water flow is at a stop.
Solid Block Activated Carbon / Charcoal Filter
Unlike granular activated charcoal, the carbon has been specially treated, compressed and bonded to form a uniform matrix. This combination of features provides the potential for greater adsorption of many different chemicals and greater particulate filtration than other types of purification methods. Effective pore sizes are usually below 1 micron. Just like any other filter cartridges, it will eventually become plugged and has to be changed according to manufacturer’s specifications.
- Certain filters are designed to better reduce specific contaminants like arsenic, lead, mercury, etc.
- Much more effective and complete than granular activated carbon filters as surface area is larger and contact time is longer.
- Pore sizes of 0.5 micron and below is small enough to prevent trapped bacteria from multiplying.
- Totally independent of electricity and water pressure.
- Nutrient from minerals like calcium, magnesium and potassium remain in the water.
- Soluble salt like nitrate and fluoride is not naturally reduced.
- Potentially harmful minerals like cadmium is not naturally reduced.
Reverse osmosis is a separation process that uses pressure to force water through a membrane with really tiny microscopic holes that retains contaminants on one side and allows pure liquid to pass to the other side. Purified water is collected from the ‘clean’ side of the membrane, and water containing the concentrated contaminants is flushed down the drain from the ‘contaminated’ side.
- Salt and inorganic matter is greatly reduced. If a carbon filter is used for post filtering, the quality will almost be as good as distilled water.
- Parasites and viruses are completely removed in properly functioning units.
- More treated water is produced compared to distillation.
- No electricity is used. Money saved.
- A proper reverse osmosis membrane lasts you at least 3 years. Money saved.
- The speed of water produced may not be enough for other uses other than drinking like cooking, washing, cleaning, etc.
- About 3 drops of water is wasted for every 1 drop of filtered water produced.
- Organic chemicals may still linger in reverse osmosis treated water.
- The membrane’s efficiency becomes unpredictable to factors like contaminant concentration, chemical properties of the contaminants, membrane type and quality, water acidity levels, temperature and water pressure.
- In situations where high water pressure is not present to force water through the membrane, it will not work.
- The pre and post filters that come with most reverse osmosis systems require changing periodically according to manufacturer’s recommendation.
- The storage tank requires regular cleaning to ensure the high quality of water stored.
- Damaged membranes are hard to notice, thus it is not easy to tell if the system is still functioning properly.
Distilled water is pure water that is obtained in a process that captures the pure steam from boiling water, which turns to liquid form again through condensation. A vapor trap, carbon filter, or other device should be used along with a distiller to ensure a more complete removal of contaminants.
- Very pure water is captured.
- Removes salt, minerals, metals, chloride and others that carbon fails to discard.
- Bacteria, viruses and protozoa is killed or left behind when water evaporates.
- Regardless of the quality of the entering water, the end result will always be high quality treated water.
- Unlike filters, there is nothing to replace.
- Long hours are required to attain a substantial amount of water. For example, it may take half an hour or longer to get 1 cup’s worth (250ml / 8.5oz) of distilled water.
- A lot of electricity is used. For example, it may cost around 0.35 cents worth of electricity to produce 1 gallon / 4 liters of water, which adds up to about $21 per month for 2 gallons per day.
- Water cannot be distilled in the absence of electricity, making it completely unattainable should an emergency arise.
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water. Water which has been treated with chlorine is effective in preventing the spread of waterborne disease.
- Commonly available in supermarket, pharmacies and convenient stores.
- Effective against bacteria and viruses.
- Initial chemical contamination in the water is not affected.
- Increases cholesterol formations.
- Carcinogenic in large amounts.
- May cause heart diseases because in the blood, chlorine reacts with calcium which causes it to become toxic and non soluble. Then it becomes plaque (breeding ground for bacteria) that eventually builds up in the body.
The most common chemical purification method used by campers. With the proper iodine concentration and a 30-minute contact time in moderately turbid water that is maintained at 20C / 70F or higher, all harmful bacteria and most viruses will be destroyed.
- Effectively kills viruses, bacteria and protozoa.
- Lightweight and convenient.
- Does not effect the cryptosporidium protozoa that can cause gastrointestinal illness with diarrhea.
- The colder the water, the more the time is needed for proper disinfection.
- Does not change the clarity of water but changes the taste.
- Iodine is only practical for short term use.
Ozone / O3
O3 is an unstable molecule which readily gives up one atom of oxygen providing a powerful oxidizing agent which is toxic to most waterborne organisms. Ozone is made by passing oxygen through ultraviolet light or a ‘cold’ electrical discharge. To use ozone as a disinfectant, it must be created on-site and added to the water by bubble contact.
- Inactivates harmful protozoa that form cysts.
- Effective against most bacteria, virus and microorganism.
- Produces less dangerous byproducts than chlorine.
- Produces trace amounts of a type of carcinogen called bromate.
- No disinfectant residual is left in the water.
Ultraviolet / UV
Water passes through a clear chamber where it is exposed to Ultraviolet light. UV light effectively destroys bacteria and viruses. However, how well the UV system works depends on the energy dose that the organism absorbs. If the energy dose is not high enough, the organism’s genetic material may only be damaged rather than disrupted.
- Very effective at inactivating cysts.
- Zero toxic byproducts.
- No added smell and taste to treated water.
- In fact, taste will improve as organic contaminants are destroyed.
- Requires very little contact time.
- Many types of bacteria, virus and microorganism are wiped off.
- Beneficial minerals are not affected.
- UV light’s disinfection effectiveness decreases as the water gets muddier, a result of the absorption, scattering, and shadowing caused by the suspended solids.
- Just like ozone, no residual disinfectant is left in the water, prompting a need to add a residual disinfectant.
- Anything that is not ‘alive’, like lead, asbestos and chlorine, are not affected by ultraviolet light.
- Will not operate without the presence of electricity.
Solar Water Distiller
A clear plastic barrier like a plastic bag, ground cloth, or a plastic grocery sack is placed over the water source. The sun passes through the barrier and heats the source which then vaporizes, rises and then condenses on the underside of the plastic barrier. The moisture collected is drinking water.
- Capable of distilling almost any tainted water including seawater.
- Drinkable water can be condensed from anything that has moisture.
- Easy to make and has low impact on the environment. All that is needed is a container to catch water and a large sheet of clear plastic.
- Source materials that give off toxins like radiator fluids or fuels are not distillable.
- The distilling process is extremely slow and only small amounts can be collected daily.
- Wild salmonella reproduces quickly when stored in the dark, requiring 10 parts per million of hydrogen peroxide to solve the issue.